Stock conduit



Aug. 26, 1930, H. FLETCHER 1,774,363

STOCK GONDUIT Filed Sept. 4J 1928 2 Sheets-Sheet l atboznews Aug. 26, 1930. H FLETCHER 1,774,363

l STOCK CONDUIT Filed Sept. 4, 1928 2 Sheets-Sheet 2 Patented Aug. 26, 1930 PATENT OFFICE HARRY FLETCHER, OF ALPENA, IICHIGAIN' srocx comm Application med september 4, 192s. serial ne. 308,375.

The present invention pertains to a'novel stock conduit for 'paper making machines, particularly of the Fourdrinier type and the principal object is to improve and simplify the feeding of stock to the wire, with the elimination of screens, head boxes, agitators, baiies, water sprays and the like.`

The problems and diiiiculties involved in the feeding of stock to the wire are well known in the art and therefore need not be discussed here. The device of the present invention accomplishes its object through the peculiar shape of the conduit itself so that the conduit alone, without the use of auxiliary appliances, effects a uniform, and efficient delivery of stock to the wire. The conduit vis constructed in such a manner as to deliver a definite volume of fluid and to reduce the velocity of its flow from;v one oint to another gradually and smoothly.

he enlargement in cross sectional area for reducing the velocity of flow is brought about by gradually increasing the width ofV the conduit until it acquires substantially the width of the flow box at its point of communication with the latter. The depth of the conduit decreases in the direction towards the flow box, but at a considerably smaller rate than the increase in width, .so'

that the result is a gradual increase in cross sectional area.

It has been found that, with a stock conduit designed in this manner, the Speed of the machine ma be increased without detriment to the de ivery of stock to the'wire and without Vthe use of accessories to the flow box.

' The invention' is fully disclosed by way of example in the following description and in the accompanying drawings in which- Figure 1 is a perspective view of the stock conduit connected tothe supply pipe and the ow box; Fig. 2 is a longitudinal section of the con-V duit, showing also convention of the Fourdrinier machine in elevation;v y Fig. 3 is a plan section on the line 3-3 of Fig. 2;

Fig. 4 is an end view of the nal section; and

Fig. 5 is a diagram showing certain characteristics of the conduit.

Reference to these views will now be had by use of like characters which are employed totdesignate corresponding parts throughou In Fig. lis illustrated the inlet end of a conventional Fourdrinier machine including a flow box 1, a breast roll 2 with a wire 3, an apron 4 leading to the wire, a deckle pulley 5 and deckle strap 6 above the breast roll, and suitable regulating means for the -deckle roll and apron. The flow box l in the iiow box 1 at the rea'r wall of the latter.

Thisconnection, commonly known as the Stock conduit, gradually increases in width from the pipe 7 to the flow box 1 and is preferably-cast in sections in order that it may take a curved form for the purpose of saving l space, although it may conceivably have a straight axisand be cast as a unitary structure. In the illustrated embodiment, however, there is an elbow 8 secured to the pipe 7 andconnected to a stockconduit section 9 whichis approximately triangular in plan view and which increases in width in the direction towards the flow box. At the wider end of' this section is provided a standard 10 for supporting a curved or' elbow section 11 having one end secured to and coincident with the larger end of the section 9. In other words, the cross ysectional areas of the abutting ends are equal, as is evident by an examination of Fig. 2 which further shows that the same relation exists between any pair of abuttingl ends of successive sections.

The abutting ends of the sections 9 and 11, as well as the remaining sections, are provided with anges 12 riveted together at 13,

whereby the joint between the sections is made. It may also be noted that the section 11 is formed with right angular legs` or props 14 which rest liatly on the standard 10.

The remaining end 15 of the section 11 is wider than the end already described, as shown in Fig. 3, and to this end is secured a straight vertical section 16 which also increases in width towards the upper end. To this end is secured, in the manner already described, another curved or elbow section 17 which is bent over in the direction of the flow box 1. The end 18 nearer the flow box is wider than the other end and has secured thereto a final straight section 19 which slopes downwardly towards the flow box and is provided'with a marginal ange 2() suitably secured around the usual inlet aperture of the box. As clearly illustrated in Figs. 1 and 4, the section 19 increases in width as it approaches the flow box, until the outlet end thereof has substantially the width of the iiow box. lThe conduit may, however, discharge directly upon the Fourdrinier wire.

It may be noted that as a'matter of construction the straight sections are in two parts provided with marginal flanges 21 secured together by rivets 22. They are also formed with longitudinal ribs 23 wherever desired' for purposes of reinforcement for radiation.

Figure 5 illustrates diagrammatically the characteristics of the conduit at points A, B, C, D, E and F along the center line. The distances from the flow box, along the center line, are plotted as abscissae along the upper edge of the diagram.V The half widths between the respective points are plotted to scale as ordinates and the heavy curve therefore indicates the change in the half widths along the centerline. The areas at the points A, B, C, D, E and F are also indicated, from which may be calculated the other dimension of the opening at these points, this dimension being referred to as the depth and designated H for convenience. The dimension H diminishes towards the iiow box, except for the point F, but at a smaller rate than the increase in width, so that an increasing cross sectional area in the direction of the flow box prevails. Itis to be understood that these iigures are illustrative of only one particular construction and may be varied Within the general characteristics stated, to meet with various conditions of individual a plications within the limits of engineering etails.

Another set of ordinates at the right hand end ofthe diagram designates velocity in feet per minute, and the lower curve shows the change in velocity for a capacity, of five hundred gallons per minute, from the point A to the flow box. The velocity obviously diminishes due to the increase in cross sectional area of the conduit.

It will be noted that the points A, B, C, D, E and F are taken at the ends of the conduit sections. These points are selected as amatter of convenience in construction, forif the dimensions of the ends of the sections are determined, each section may be built to vary gradually from one end to the other. For example, in the case of the straight sections, it is merely necessary in designing to connect orresponding points at the ends by straight mes.

As' will be seen the direction of length of the conduit is such that a back pressure condition is setup within the conduit itself by the linear shape of theconduit, with the result that although the cross-sectional area of the conduit increases as the l conduit progresses, the conduit itself remains full, the velocity decreasing, thus delivering the material in sheetlike form and at the velocity` which is desirable, and while delivering the material to the conduit itself at acomparatively high velocity. For instance, in the illustration used, the velocity at the inlet end of the conduit is approximately ten times that present at the discharge end, the decrease being gradual due to the length of the conduit and the change in cross-sectional area. However, the decrease in velocity is so developed that approximately of the decrease' is presented in theinitial third of the length of the conduit, the inal third presenting a relatively slow decrease in velocity, soA that the material, as it approaches its sheet-like form, reaches this condition gradually and without violent changes in velocity conditions.

It has been found in practice that a stock conduit constructed to have a generally increasing width in cross sectional area in the direction of the flow box until the outlet end has substantially the width of the box improves the operation, eliciency and permissible speed of the machine in the manner already set forth.

Although a specific embodiment of the invention has been illustrated and described, it will be apparent that various alterations in the details of construction may be made Without departing from thel scope of the invention as indicated by the appended claims.

What I claim is 1. A stock conduit having an inlet end adapted for connection to a source of supply, and an outlet end adapted to discharge into a ilow box or directly upon a Fourdrinier wire, said conduit increasing in width from the inlet end to the outlet end, thexdirection of length of the conduit being such as to produce a back pressure condition within the conduit by the linear shape of the conduit between its ends.

2. A stock conduit having an inlet end adapted for connection to a source of supply, .and an outlet end adapted to discharge into a flow box or directly upon a Fourdrinier wire, said conduit increasing in width from the inlet end to the outlet end, and having at the latter end substantially the Width of said box, the direction of length of the conduit being such as to produce a back pressure condition Within the conduit by the linear shape of the conduit between its ends.

3. A stock conduit having an inlet end adapted for connection to a source of supply, and an out-let end adapted to discharge'into a flow box or directly upona Fourdrinier Wire, said conduit increasing in width and area from the inlet end to the outlet end, the increase in area being such as to provide a decrease in velocity of a proximately 70% withinkthe initial third o the length of the conduit.

4. A stock conduit having an inlet end adapted for connection to a source of supply,

and an outlet end adapted to discharge into a flow' box or directly upon a Fourdrinierv Wire, said conduit increasing in Width from the inlet end to the outlet end, and diminishing in depth in the same direction and at a smaller rate, so that the area increases from the inlet end to the outlet end, the increase in area'being such as to provide a decrease in velocity of approximately v7 0% within the initial third of the length of the conduit.

5. A stock conduit having an inlet end adapted for connection to a source of supply, andan outlet end adapted to discharge into a iow box or directly upon a Fourdrinier wire, said'conduit increasing in Width and area from the inlet end tothe outlet end, and having at the outlet end substantially the Width of said box', the increase in area being such as to provide a. decrease in velocity of approximately 70% Within the initial third of the length of the conduit.

In testimony whereof' I ailix my signa ture.

HARRY FLETCHER. 

